Hi,

Please know the difference between Basic authentication and NTLM authentication for Outlook Anywhere:

Basic authentication: If you select this authentication type, Outlook will prompt for username and password while attempting a connection with Exchange. Outlook 2010 and lator version are using "Remember my Credentials" to save credentials for Basic authentication.

NTLM authentication: If you select this authentication type, exchange does not prompt users for a user name and password. The current Windows user information on the client computer is supplied by the browser through a cryptographic exchange involving hashing with the Web server. If the authentication exchange initially fails to identify the user, the browser will prompt the user for a Windows user account user name and password. So, when Outlook is trying to connect to Exchange and if the machine is domain joined, there isnt a need to provide password.

If the saved credentials cause your Outlook problem, the issue should not be related to Exchange server. Please clear all saved credentials in Windows machine with Outlook closed, and restart Outlook without "Remember my Credentails" to have a try. Additionally, here are some articles for your reference:

https://support.microsoft.com/en-us/kb/2762344

https://support.microsoft.com/en-us/kb/2708705

Regards,

Thank you Winnie for the response. I am quite familiar with the different authentication types. The problem I was asking about is the fact that my credentials were being saved when I wasn't clicking the "save my password" option.  I never use that option and I also instruct my users to not use that option either.

When connected externally I get the login box for my outlook credentials (Which is normal since I'm using the external Basic over SSL connection).  After that login prompt, I get the login prompt for the public folder mailbox which keeps popping back up no matter what credentials I put in.

Now if I remove the saved credentials in credential manager (remember that I never clicked "save my password"), I get the expected behavior where I only have the one login prompt when I start Outlook up and I can connect to the public folders and any shared mailboxes fine without any additional login prompts

So, I was wondering why these entries keep getting created when I never save any passwords and is there any way to prevent this from occurring with Outlook 2013.

We have an issue with Windows 7/8 clients and Outlook 2013 where user credentials are being saved in the credential manager (in control panel on the users workstations) and causing login prompts to the public folder mailboxes and shared mailboxes.  On my windows 8 workstation, I have a saved credential under "Generic Credentials" related to Outlook 2013 and I've never click the "save password" check box.  It will work fine until I have to change my network password and then the issues will start.  Once the issues with the login prompts start (putting in the login ID and password doesn't work), deleting the saved credential "MS.Outlook.15:{Login ID}" always fixes the problem.  Once I delete the saved credential, it always comes back after a few days.

My question is why are my credentials being saved when I never ask them to be saved? 

We're configured for NTLM Authentication inside and Basic over SSL externally.  I don't see any other issues with authentication until that entry in credential manager gets out of whack.